Treatment of steel roping wire

ABSTRACT

Steel wire which is at its final size is provided with a manganese phosphate coating imparting wear resistance. The wire can be made up into strand and rope. The coating can be sealed with a corrosion resistant sealant.

United States Patent 1191 Guy 1451 Aug. 12, 1975 TREATMENT OF STEEL ROPING WIRE [75] Inventor: Raymond Guy, Skellow, near [30] Foreign Application Priority Data Aug. 18, 1972 United Kingdom 38614/72 [52] U.S. Cl 148/6.l5 R; 57/153; 57/162 [51] Int. Cl. C23F 7/08 [58] Field of Search 148/6.15 R; 117/128;

[56] References Cited UNITED STATES PATENTS 1,206,075 11/1916 Allen 148/6.15 R

3,188,791 6/1965 Grimes et a1. 57/145 3,450,578 6/1969 Siemund et a1. 148/6.l5 R

OTHER PUBLICATIONS Bader, Chem. Abstracts, V01. 681425395, (1968).

Primary ExaminerRa1ph S. Kendall Assistant ExaminerChar1es R. Wolfe, Jr.

Attorney, Agent, 0r.FirmJohnson, Dienner, Emrich & Wagner ABSTRACT Steel wire which is at its final size is provided with a manganese phosphate coating imparting wear resistance. The wire can be made up into strand and rope. The coating can be sealed with a corrosion resistant sealant. v

4 Claims, No Drawings TREATMENT OF STEEL ROPING WIRE This invention relates to the treatment of steel wire, such as roping wire, brush wire, armouring wire, and music wire, for example. The wire to be treated is at its final size, i.e. all the drawing steps have been completed.

It is common practice to apply an intermediate or drawing coat to suitably prepared steel rod or wire prior to, and as an integral part of, the operation of multi-hole drawing. Phosphate complexes are often included. Phosphate coatings strongly adhere to the underlying steel and have a particular crystalline structure which enables them to adsorb and retain an appreciable amount of wire drawing lubricant. It is also known that a manganese phosphate can be deposited onto ferrous wire before drawing, but, unexpectedly, this does not confer any properties which facilitate the cold drawing of roping wire.

The present invention is the result of an investigation into possible ways of improving the lubication and corrosion resistance of ropes employed in friction winders. However the resulting invention has utility in a wide variety of wire products.

Friction winders depend upon the maintenance of a coefficient of friction between the rope and the sheave at a value of 0.2. Any lubricant permeating to the exterior of a rope reduces this value and can result in loss of traction and slip. Conversely, to reduce the amount of lubricant within a rope, to a level which prevents surface exudation, often causes internal corrosion and fretting.

The present invention provides a method of treating steel wire which is at its final size, comprising forming a manganese phosphate coating on the steel wire.

The invention also provides a steel wire having a manganese phosphate coating.

The invention further provides a steel wire strand or rope in which each wire (or at least each wire in the outer layers) has a manganese phosphate coating.

The coating is preferably oil-sealed; the oil sealant can be applied to the coated wire, the strand. or the rope.

The invention also provides a method of manufacturing a steel wire strand or rope, in which wires to be stranded are provided with a manganese phosphate coating.

Preferably an oil sealant is applied to the coated wires before stranding.

It was unexpectedly found that a coat of manganese phosphate applied to the finished wire prior to stranding not only fulfilled the anticipated requirements, but proved superior to the other types of phosphate coating.

The formation of manganese phosphate coating is analogous to that of a zinc phosphate coating, consisting primarily of a hydrated tertiary manganese phosphate together with small amounts of an iron manganese phosphate.

The wire coating may be applied by spray or immersion, the optimum thickness being controlled by (a) the original state of the steel surface, (b) the preliminary preparation of the wire surface, and (c) the nature of the metal treated.

The spray or immersion method can be used to coat wires on an in-line basis, in which individual wires are passed either singly or in multiples continuously through the treatment chemicals. Or a batch process can be applied in which wires in coil form are exposed to the treatment chemicals.

EXAMPLE The cleaning and coating process utilised is as followsz- 1. Removal of wire drawing residues, i.e. pigmented drawing compounds, drawing oils, greases, waxes, etc., from the wire surface. This can be achieved by solvent degreasing, vapour degreasing emulsion cleaning, or alkaline degreasing. The preferred method is alkaline degreasing, which utilises the saponifying and emulsifying effect of aqueous alkalis reinforced by sequestrating, complexing, and surface active agents. The ingredients can be sodium hydroxide, sodium carbonate, sodium metasilicates, tri-sodium phosphate, sodium pyrophosphate, sodium borates, complexing agents (such as EDTA, gluconates, heptonates, polyphosphates, and cyanides) and organic surfactants. They may be used hot or cold with or without applied current, which may be either anodic or cathodic. A preferred proprietary alkaline cleaner is Pyroclean 303, which may be applied by either spray or immersion. The preferred method is by immersion.

The solution can operate over a temperature range of 15C to C, but the preferred range is 82C 99C.

The concentration range utilised can be from 0.5 oz to 50 oz per gallon (imp) but the preferred concentration is 3 oz/gallon (imp).

The immersion time can vary from 1 to 30 min depending upon the soil to be removed, but experience has shown that 15 min is sufficient to give the desired result.

2. A water rinse is utilised to remove any excess alkaline solution. This system can either be spray, immersion or both and the temperature can be ambient to boiling. The preferred method is a spray rinse, followed by a cold freerunning-water dip, followed by a spray rinse.

3. The wire is then passed, without drying, into a pretreatment solution which activates the metal surface in order to facilitate formation of a fine grained manganese phosphate coating. The preferred pretreatment chemical utilised is Parcolene VM, although other proprietary chemicals could serve equally well.

The operating solution is prepared by adding Parcolene VM C powder at the rate of 3 lb for each 100 gallons of solution required. Then continuous agitating equipment, i.e. paddle type stirrer or compressed air, is turned on and the Parcolene VM A powder is added at the rate of 3 lb for each gallons of solution required. The bath is then brought to the operating level by the addition of the necessary water and heated to the operating temperature, which may be in the range of l6C to 60C. The wire, wet with water from the rinse system, is then immersed in the Parcolene VM for l 10 minutes.

The temperature at which the Parcolene VM is operated depends upon the degree of refinement of the manganese phosphate coating required. In general it has been found that higher temperatures lead to greater refinement whereas lower temperatures lead to longer bath life.

The preferred method is ambient temperature with an immersion time of 5 min.

4. The wire, wet from the pretreatment process, is then treated with manganese phosphate solution. These solutions produce a superficial layer of insoluble complex phosphates by chemical reaction with the metal surface. This reaction is produced by slightly acid (pH 2 3) aqueous solutions based on monometallic orthophosphates (i.e. manganese) and free phosphoric acid. As a rule the solutions contain one or more oxidising agents which act as depolarisers or reaction accelerators, such as nitrate, nitrite, chlorates. etc. and sometimes with substances that help to produce a finer coating, such as polyphosphates, nickel or calcium salts.

The preferred chemical is Parco-Lubrite 2, and the method of treatment is by immersion for 15 min at a temperature of 95C. The preferred pointage for the bath, which is a value based upon titration of a ml sample of the solution with N/5 NaOH, is 28 32 points.

5. A water rinse is utilised to remove excess phosphating solution. The preferred operation of this rinse is the same as for after the alkaline degreasing.

6. The coating is then dried, which can be achieved by hot air blowing, hot air oven, flash baking, etc. The preferred method is a hot air recirculating oven at a temperature of 150C, although a range of temperatures from 100C to 250C can be used. The wire is left until dry, but it has been found that min is sufficient.

7. Following the drying procedure the manganese phosphating is sealed to confer extra corrosion resistant properties on the material. The sealants used can be organic compounds of the oil type (non-setting mineral oils of various weights and viscosities), the solvent type (petroleum base film forming materials and rust inhibitors dissolved in petroleum solvents), emulsifiable type (petroleum base rust preventativcs modified to form stable emulsion when mixed with water), or the wax type. Inorganic sealants of the chromate, dichromate type may also be used. The sealants may be applied by brushing, spraying, dipping, flushing, etc.

The preferred material is an oil based solvent cut back solution, namely Parker Finish P75 and the preferred application methods are by immersion or spray ing. It can be applied at temperatures from 15C to 50C, preferably at 50C. [f spraying is used the solution is kept at room temperature.

When compared with untreated steel wire or steel wire coated with a zinc phosphate, the manganese phosphate coating was seen to give:

i. Very rapid wetting and diffusion of oil, with the re tention of twice as much oil when drained.

ii. Superior resistance to friction and seizure, indicated by tests on a shell 4-ball machine.

SHELL 4-BALL MACHINE This comprises a compact assembly of 4 identical balls, three of which are clamped in a conical sided container; they are centred and remain stationary. The fourth ball is secured to a motor shaft and turns at a constant speed (1500 rev/min). The container is mounted on a cradle which can transmit the test load so that the three fixed balls are pressed against the fourth by the load.

Hertz load curves can be drawn which relate the wear scar diameter to the load. The scar diameter increases progressively; seizure (welding of the balls) occurs at a certain load when the temperature is high enough.

Untreated Balls Phosphated kg Balls kg Mean Hertz Load 14.76 58.50 Weld Load 1 15 316 The mean Hertz load is the mean of the corrected loads P P load applied (kg) D scar diameter (mm) d scar diameter in mm due to static load P The following table shows the results of tests carried out on the Shell 4-Ball machine, of l min duration, using as a lubricant a pure mineral oil of naphthenic origin. Zinc phosphated, manganese phosphated, and untreated balls were tested.

MEAN SCAR DIAMETER (mm) PHOSPHATED BALLS Load Untreated Zinc Zinc Manganese (Kg) Balls Phosphate A Phosphate B Phosphate 340 Welding at 10 secs. 320 L28 280 Welding at 10 secs.

260 0.98 240 Welding at 0.88 l.l0

10 secs.

Welding It will be seen that the maximum weld load for manganese phosphate is much higher than that for zinc phosphates, viz.

Manganese Phosphate 340kg Zinc Phosphate A 240kg Zinc Phosphate B 280kg Untreated Balls l20kg is accelerated with chlorate and contains nickel;

is accelerated with nitrate and contains nickel.

Zinc Phosphate A Zinc Phosphate B During the same tests it was noted that the manganese phosphate reduced the coefficient of friction from 0.3 to 0.08

iii. Excellent wear resistance and superior hardness. Whilst the wear resistance qualities are mainly attributable to the excellent bond the coating forms with the surface of the steel, its superior hardness (compared with a zinc phosphate coat) is also regarded as a contributory factor. On the Mohs scale. the hardness of the manganese phosphate coating was 5.0 and zinc phosphate 3.0. The rate of wear of a manganese phosphate coating was independent of its thickness, whereas the rate of wear of a zinc phosphate coating increased with its thickness.

iv. Reduced fatigue induction in association with fretting corrosion. The effect of fatigue failure and fretting corrosion especially when promulgated in association with one another is'an ever present problem in all steel wire ropes, but particularly Locked Coil ropes. When tested under purely fatigue conditions, a piece of manganese-phosphate-treated steel gave only marginally better results than untreated steel, but when the fatigue induction was simultaneously associated with fretting corrosion a major improvement in the fatigue resistance of the manganese phosphate coated steel was noted compared with the untreated sample, which showed a markedly lower resistance to fatigue induction when in association with fretting corrosion.

v. Improved corrosion resistance. In the salt droplet test an oil-sealed manganese phosphate coating lasted for 2,000 hours compared with the 650 hours of a simi larly treated zinc phosphate coating.

Extension of this test to include a comparison with electroplated zinc showed that, when the coating thicknesses were equal, a manganese phosphate coating was superior.

The tests were repeated, applying an oil sealant to the electroplated zinc and the manganese phosphate coating, and although this improved the performance of the zinc coating, it failed to put it on a parity with the manganese phosphate coating.

Comparisons of the corrosion resistance of a manganese phosphate coating, sealed with P75 oil, versus hot and electro-galvanised coatings, have been made. The test conditions were a salt spray to ASTM Bll7-64 using a 5% sodium chloride solution at 35C, and a cyclic humidity test to BS3900. These results are given in the following Tables 1 and 2.

TABLE 1 SALT SPRAY ASTM Bl l7-64 TABLE 2 HUMIDITY TEST BS3900 down of coating with heavy red rust formation TABLE 2 HUMIDITY TEST BS3900 To summarise, it has been established that the coating of drawn steel roping wire with an oil-sealed manganese phosphate layer prior to its being made up into strand or rope, enables a greater amount of lubricant to be retained within the strand or rope. This, in conjunction with the superior characteristics of the manganese phosphate over what was previously known, has resulted in greatly improved rope performance.

I claim:

1. A method of manufacturing steel wire strand or rope from steel wires which are at their final size, comprising the sequential steps of:

cleaning the wires,

forming a manganese phosphate coating on the wires,

and

stranding the manganese phosphate coated wires to form a strand.

2. A method of manufacturing steel wire strand or rope from steel wires which are at their final size. comprising the sequential steps of:

cleaning the wires to remove wire-drawing residues,

rinsing the wires with water,

activating the wires, which are still wet, by means of a pre-treatment solution facilitating subsequent formation of a fine-grained manganese coating, forming a manganese phosphate coating on the wires.

which are still wet with the pre-treatment solution, rinsing the coated wires with water,

drying the wires,

sealing the coating of the wires with a corrosion resistant sealant selected from the group consisting of organic compounds of the oil type (non-setting mineral oils of various weights and viscosities), the solvent type (petroleum base film forming materials and rust inhibitors dissolved in petroleum solvents), emulsifiable type (petroleum base rust preventatives modified to form stable emulsion when mixed with water), wax type, and inorganic sealants of the chromate and dichromate type, and stranding the wires to form a strand.

3. A method as claimed in claim 1, further comprising the step of sealing the coating with a corrosion resistant sealant selected from the group consisting of organic compounds of the oil type (non-setting mineral oils of various weights and viscosities), the solvent type (petroleum base film forming materials and rust inhibitors dissolved in petroleum solvents), emulsifiable type (petroleum base rust preventatives modified to form stable emulsion when mixed with water), wax type, and inorganic sealants of the chromate and dichromate type before stranding.

4. A method as claimed in claim 3, in which the sealant is an oil. 

1. A method of manufacturing steel wire strand or rope from steel wires which are at their final size, comprising the sequential steps of: cleaning the wires, forming a manganese phosphate coating on the wires, and stranding the manganese phosphate coated wires to form a strand.
 2. A METHOD OF MANUFACTURING STEEL WIRE STRAND OR ROPE FROM STEEL WIRES WHICH ARE AT THEIR FINAL SIZE, COMPRISING THE SEQUENTIAL STEPS OF: CLEANING THE WIRES TO REMOVE WIRE-DRAWING RESIDUES, RINSING THE WIRES WITH WATER, ACTIVATING THE WIRES, WHICH ARE STILL WET, BY MEANS OF A PRE-TREATMENT SOLUTION FACILITATING SUBSEQUENT FORMATION OF A FINE-GRAINED MANGANESE COATING, FORMING A MANGANESE PHOSPHATE COATING ON THE WIRES, WHICH ARE STILL WET WITH THE PER-TREATMENT SOLUTION, RINSING THE COATED WIRES WITH WATER, DRYING THE WIRES, SEALING THE COATING OF THE WIRES WITH A CORROSION RESISTANT SEALANT SELECTED FROM THE GROUP CONSISTING OF ORGANIC COMPOUNDS OF THE OIL TYPE (NON-SETTING MINERAL OILS OF VARIOUS WEIGHTS AND VISCOSITIES), THE SOLVENT TYPE (PETROLEUM BASE FILM FORMING MINERALS AND RUST INHIBITORS DISSOLVED IN PETROLEUM SOLVENTS), EMULSIFIABLE TYPE (PETROLEUM BASE RUST PREVENTATIVES MODIFIED TO FORM STABLE EMUSLION WHEN MIXED WITH WATER), WAX TYPE, AND INORGANIC SEALANTS OF THE CHROMATE AND DICHROMATE TYPE, AND STRANDING THE WIRES TO FORM A STAND,
 3. A method as claimed in claim 1, further comprising the step of sealing the coating with a corrosion resistant sealant selected from the group consisting of organic compounds of the oil type (non-setting mineral oils of various weights and viscosities), the solvent type (petroleum base film forming materials and rust inhibitors dissolved in petroleum solvents), emulsifiable type (petroleum base rust preventatives modified to form stable emulsion when mixed with water), wax type, and inorganic sealants of the chromate and dichromate type before stranding.
 4. A method as claimed in claim 3, in which the sealant is an oil. 